The Study of a Small Scale Catalytic Combustor for TPV Generation System

Paper number

IAC-08.E2.1.1

Author

Mr. Go Ohmura, Osaka University, Japan

Year

2008

Abstract

Due to developments of portable electronic devices / appliances, a small electric generation system, driven by hydrocarbon fuels is expected as a promising high density generation system instead of conventional rechargeable batteries.  We focused on a thermophotovoltaic (TPV) generation system which has a lot of advantages such as high reliability as well as little demerits of the size reduction.  In our research, to develop a small scale and high intensity heat source and to establish the method of controlling wavelength of NIR radiation, we proposed the new concept of TPV generation system; the feature of our system is a small scale catalytic combustor using the sphere-shaped pallet catalysts, which are for generating and controlling NIR as heat source / emitter and lower activation energy necessary for the combustion reaction.  The discussions were mainly conducted through experimental methods (direct images, temperature measurement, exhaust gas analysis, spectrum measurement, power generation measurement) whether the proposed concept is useful for the TPV generating system and what is the governing phenomena on each component of the TPV generation system (especially catalytic combustion).
In the present paper, we developed several geometric types of the small scale catalytic combustors using the pellet catalysts for investigating the catalytic combustion phenomena and the effective operation conditions.  The NIR spectral measurements showed that the emission from the catalytic combustor contained the NIR spectra.  Moreover the GaSb cell generated the electric energy using the emission from the catalytic combustor.  It is confirmed that our proposed concept is applicable to the TPV generation system and the pellet catalysts in the combustor could play a role of an emitter for the TPV generation system.
Direct image observation, temperature measurement and exhaust gas analysis showed that supplying the premixed gas of fuel and air at high equivalent ratio, but not more than unity, into high temperature region of the combustor and the dividing supplying system (i.e. supplying the fuel not only from one port but from several ports) are useful for the improvement of the combustion efficiency.
The ultraviolet and visible spectra measurement showed that the local chemiluminescence was not confirmed from the catalytic combustion which occurred inside the developed combustor.    It can be considered that the surface chemical reaction was predominant in the catalytic combustion and the gas phase reaction which causes higher temperature and higher reaction rate than that of surface reaction was not occurred in the developed combustor.

Abstract document

IAC-08.E2.1.1.pdf

Manuscript document

IAC-08.E2.1.1.pdf (🔒 authorized access only).

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